Automatic transmission



JNM 14, 1947- H. E. cARNAGuA ETAL 2,414,359

AUTOMATIC TRANSMIS S ION 3 Sheets-Sheet 1 Filed` D'ec. 16. 1943 Jan 14,1947. H. E. cARNAGuA Erm.` 2,414,359

AUTOMATIC TRANSMISSION Filed Dec. 16, 1943 3 Sheets-Sheet 2 J/MM Jgn.14, 1947. HI E. cARNAGuA ErAL 2,414,359

AUTOMATIC TRANSMISS ION Www@ Patented- Jan.1 14, 1947 Harold E. Carnaguaan Muncie, Ind., assignors d Donald to Borg-Warner Corpo- W. Kelbel,

ration, Chicago, Ill., a corporation of Illinois Application December16, 1943, Serial No. 514,464

This invention relates to power transmitting devices and particularly tosuch devices incorporating an infinitely variable hydro-dynamic devicecombined with gearing.

object of this invitation is to times for greater efiiciency, withadditional means for providing a neutral to prevent creep, a low rangeand alhigh range and also a reverse drive.

Another object of this invention is to provide, in a transmissionemploying an infinitely variable torque multiplying hydro-dynamic devicebe transmitted Y serving to connect shaft I2 to the combined withgearing, a friction clutch at the output of the torque multiplyingdevice, said friction clutch being physically located between the torqueconverting device and the internal.l

combustion engine with which the transmission is used so as to permitthe use of a large diameter friction clutch without unduly increasingthe size of the transmission casing. Y

Another object of this invention is to provide a more compactarrangement of the parts and to provide power shifting throughout thetransmission.

These and other objects of this invention will become apparent from thefollowing detailed description when taken together with the accompanyingdrawings in which:

Fig. 1 is a schematic functional diagram of the power transmittingelements of one embodiment;

Fig. 2 is a section taken through one embodiment of this invention; v

Fig. 3 is a transverse section through the embodiment of Fig. 2 takenalong line 3 3 of Fig. 2;

Fig. 4 is a functional diagram of another embodiment of this invention;and

Fig. '5 is a partial section taken through a transmission incorporatingthe features of the embodiment of Fig. 4.

Referring now to Fig. 41 for a functional description of thetransmission, power from a prime I mover, such as an internal combustionengine (not shown) is impressed upon an input shaft I0 which isconnected directly to a power splitting differential MII, a portionofthe power being transmitted mechanically to an intermediate 'structureor shaft I2 and the remainder being transmitted to an infinitelyvariable torque multiplying device such as a varied-type hydrodynamictorque converter I3, the torque from I shaft I isnot rotating and vgineby turning driven shaft 15 Claims. (Cl. 74-189.5)

torque converter I? being combined in structure I2 with the portiontransmitted directlythereto by the power splitting differential II.

The torque in intermediate structure I2 may be again multiplied by meansof planetary gearing I4 to provide a low range operation, or it maydirectly to a driven shaft I5 for highrange operation. Whether or notthe torque is again multiplied depends upon the operation of frictionclutches I6 and I1, friction clutch I6 a torque multiplication andclutch I1' serving to connect shaft I2 directly to the driven shaft I 5when no torque multiplication is desired.

The reaction for torque multiplication is provided by abrake I 8 whichhas suitable connecbothv the torque converter I3 and planetary gear setI4.' However, a one-way connection I9 is used between brake I8 andtorque converting device I3 so as to permit the entire device I 3 torotate forwardly withouteffecting any torque multiplication when thefluid conditions gear set I4 is a permanent connection, clutches I6 andI1 are mutually exclusively operable lto prevent planetary gear set I4from being locked up and held in braked position when direct drive isdesired.

A direct connectionv including a ratchet clutch 20 and a shaft 2| isprovided between driven shafts I0 and I5 in order to crank the en-I5.for a push start. Clutch l2|) is automatically engaged when drive isautomatically disidling. 22 is provided which engaged when the engine isFor reverse drive, a brake is applied to the turbine element of thevaned torque' converter I3 when thereaction element or stator thereof isnot held against rotation by brake I8. With clutch I6 engaged and clutchII disengaged it will be observed that brake 22 also provides a reactionelement for both planetary gear sets Il and I 4 as well as causing theturbine and reaction elements of the torque converter I3 to exchangefunctions so that the turbine element becomes the stator and the statorelement becomes the turbine. VThe result is a reverse drivein drivenshaft I5v through the converter I3 as will be described in detailhereinafter.

When this transmission is used in an automotive vehicle such as apassenger car. for example,

driving and of a sun gear 31 -3' itis contemplated that the rear axleratio in the vehicle will be in the neighborhood of 4.25 to l andaccordingly an overdrive mechanism 23 may be used between driven shaft Iand the rear axle to slow down the engine at high vehicle speed.

Referring now to Fig. 2 for a detailed description of the embodiment ofthe elements described in Fig. l, drive shaft I0 is connected tosplittingdiiierential II by means of a fly-wheel 24 and a drum 25. Thepower splitting differential Il is comprised of a ring gear 26 which issecured to drum 25 so as to be rotatable therewith and which meshes withone or more planet gears 21 each of which in turn meshes with anotherplanet gear (not shown). The said other planet gears mesh with a sungear 28. -This form of dual planet gearing is well known in the art andits characteristics need not be described in detail here. Planetlpinions 21 are mounted on a carrier 29 which is connected on one sideto a brake drum 30 and on the other through a concave disc 3| to aninner drum 32.

Torque converter I3 is comprised of a pump element 33 which is bolted tosun gear 28, a turbine element 34 which is splined to drum 32 and astator element 34a which is connected by means of the aforementionedone-way coupling device I9 to a shaft 35. A brake drum 36 is splined tothe right-hand end (Fig. 2) of shaft 35, said drum constitutingtherotatable element of brake I8. V

The torque multiplying gear set I4 is comprised which meshes with agroup of planetary gears (not shown) which in turn meshes with a secondgroup' of planetary gears 38 to form a. dual planetary gear set of thetype shown at I I and used as a power splitting device. Said secondgroup of planetary gears 38 meshes with a ring gear 39 which drivesoutput shaft I5 through the webl 4I'I.` Planet pinions 38 are mounted ona carrier 4I which is splined to the driven element 42 of clutch I6.Said clutch I6 is of the conical type so as to have the greatestcapacity for the smallest area of cooperating friction surfaces. Thedriven element 42 is operated by a piston 43, preferably made ofstampings to reduce its rotational. inertia, said piston forming a'chamber 44 between itself and turbine element 34 into which fluid underpressure may be admitted. The fluid pressure acts in a direction toengage the clutch, and a spring 45, reacting against carrier 4I, servesto disengage the clutch.

Piston 43 is retracted by means of a plurality of springs 46 tensionedbetween the piston and a loop of wire 41 retained in a groove -48 inturbine member 34. Contact between piston 43 and movable element 42 isestablished by means of a friction facing 49 which is riveted to movableelement 42. The xed element of clutch I6 is comprised of a ring 5IIwhich is also splined to drum 32 and has a conical surface 5I adapted tocooperate with the conical surface on movable element 42, and anotherconical surface 52 which forms one of the axially fixed frictionsurfaces of clutch I1.

The connection between ring gear 39 and turbine element 34 as statedpreviously is elected by means of friction clutch I1. This clutch, inaddition to the fixed conical surface 52, is provided with a second andoppositely inclined surface 53 formed in a ring 54 splined to drum 32.Cooperating with surfaces 52 and v53 are movable elements 55 and 56which 'are so formed that element 55 provides an annular recess andelement 56 constitutes an annular piston operating in said -slot 59 inforging 49, and

19 and end plates 80 the uid then passes elements to engage surfaces 52and 53. Element y 58 which extend into a piston 56 is likewise providedwith lugs 60 which extend into a slot 6I in forging 49 disposed oppositeslot 59. The clutch is maintained in a retracted position by means ofa'series of springs 62 which are tensioned between a pair o f hoops63positioned outside of lugs 58 and 69.

Clutch 29, which it'will be recalled is used to start the engine fromthe driven shaft I5, is comprised of a set of ratchet teeth 64 formed ina piston 65 which is keyed to drive shaft IIJ, and a cooperating set ofratchet teeth 66 formed in the end of shaft I5. Said shaft I5 is boredto receive piston 65.y in an opening 68 55 is provided with lugs and iscompressedagainst an 20 in an engaged condition. Thus whenever fluidpressure behind piston 65 is reduced below the force of the spring 61,clutch 29 will be engaged.

Fluid for disengaging clutch 20, for lubricating portions of thetransmission and for filling torque converter I3 is obtained from asuitable source of fluid under pressure. such as the engine oil pump andis conducted to a conduit 10 formed in housing 1I and leading to anannular space 12 formed between driven shaft I5 and shaft 35. Saidannular space through a conduit 13 with hydraulic torque converter I3, aconduit 14, a return conduit 15 and the series of conduits and spacesshown in Fig. 2

(not shown) from the same fluid source and conducted through conduit 11to a series of connected conduits as shown in Fig. 2 to the space 51behind piston 56.

To simplify the drilling of the driven shaft I5 for the various conduitsand passageways,`driven shaft I5 is drilled with one continuous bore |92into which is tted a long plug |03, the plug .being previously formedwith portions of reduced diameter and with a central passageway havingappropriate openings to the exterior at either end.

Brakes I8 and 22 are 3. Said brakes comprise a .cylinder 18 formed inhousing 1Ivin which is a double acting piston 19. The ends of cylinder18 are closed off by end plates 89 and 8I and resilient means such ascoil springs v82 and 83 are compressed between piston and 8l. Thepressure of springs 82 and 83 is not taken directly by piston 19 but byapertured stampings 84 and 85 each of which is anchored to a piston rod86v and 81 respectively. Said rods are provided with shoulders 88 and89, respectively, which limit theinward movement of the rods. In orderto move .one of the rods, for example rod 81,A outward, fluid underpressure is admitted through a conduit 90 into the opposite halfofcylinder 18 and through the apertured stampings 84 to piston 19,thereby forcing the piston to the right as viewed in Fig. 3 against Arelease spring 61 is received 12 is in communication A likewise throughsuitable valving` shown to advantage in Fig.

stamping 85 to move rod 81 outward. A similar The movement of each rodis transmitted to the respective brakes by suitable linkage. As anexample of one form of linkage, rod 81 is connected through apin-and-slot connection 9| to a bell crank 92 which is pivoted at 93 toan anchor block brake band 94. VSaid brake band 94 cooperates with drum36 of brake I8. A spring 95 tensioned between housing 1| and a lug 96 onanchor 94` tends to rotate the end secured thereto in a counterclockwisedirection as viewed in Fig. 3. The opposite end 91 of brake bannd 94 issecured to an anchor block 98 which is pivotally connected at 99 to abeing pivoted at its opposite end IUI to bell crank 92. It will beapparent from the arrangement of the various links and anchor blocksthat when piston rod 81 is moved to the right as viewed in Fig. 3 theends of the brake band will be drawn together to eiect its tighteningabout its associated drum, thereby causing the brake to become operativeto arrest the rotation of shaft 35. It will alsobe observed that spring83 in cylinder 'I9 and spring 95 will tend to release the brake. Asimilar arrange ent may be used to operate the brake 22. A y

Details of the overdrive mechanism 23 are not given here since it iscontemplated that the overdrive will be of standard design such as hasbeen on the market for many years.

The transmission herein described provides a denite neutral through thedisconnection of the turbine element 34 from the planetary gear set I4and hence when properly controlled the transmission will not creep as iscustomary in hydrodynamic transmissions which are directly connected toan internallcombustion engine. The arrangement of parts is such thatalthough the clutch I6 is required to transmit more than engine torqueand hence must be sufliciently large to carry this load it is locatedadjacent the flywheel where ample room is available althoughfunctionally it is associated directly with the driven shaft. Clutch I1which is required to carry only engine torque, is located adjacentclutch I6 and likewise `does not unduly increase the size of thetransmission. Although both clutches may be engaged abruptly, the torqueat all times is transmitted, at leastpartly, through the torqueconverter I3 which is inherently a and thel remainder beingtransmi'ttedto an innitely variable torque multiplying device such as a vaned typeof hydro-dynamic torque converter II3, the torque from converter ||3being combined in intermediate structure I|2, with the tension rod |00,said rodl 'o friction clutch m 6 portion transmitted directly thereto bythe power splitting diiierential I I i.

The torque in intermediate shaft uzvmaybe again multipliedby means ofplanetary gearing I I4 to provide a low range operation, crit` may betransmitted directly to a driven shaft ||5 for a high range. v'I'hepower from intermediate structure ||2 is transmitted to planetarygearing ||4 through a one-way clutch ||6 which is arranged to preventstructure ||2 from rotating ahead ofgearing III but will release whensaid gearing is'l rotated faster than structure ||2. A serves` toconnect structure 2 directly to the torque multiplication is desired.

'I'he reaction for torque multiplication is provided by a brake I I8which has suitable connections to both the torque converter I I3 and theplanetary gear set I vice I I3 to rotate forwardly without effecting anytorque multiplication when the uid conditions therein warrant suchoperation.

structure ||2 and planetary gear set I|4 being automatically released byone-way clutch IIS. A direct connection ratchet clutch similar to theone shown in Fig. 2 may be used between drive shaft ||0 and driven shaft||5 for purposes and is shown at |20 in Fig. l.

For reverse drive a braker|22 is provided which is applied to theturbine element of the varied torque converter' ||3 through one-wayclutch I I6 when the brake II8 is released. Since one-Way clutch IIGdoes not permit structure ||2 to rotate ahead of the gearing II4, theclutch will be effective to hold the turbine element..

Referring now to Fig. 5'for a detailed description of the secondembodiment of the invention, planetary` gear 'sets I II and I I4 are ofthe dual planet type as described with reference to the the connectionbetween drive shaft |I|l and planetary gear set III is effected througha flywheel |24 and. a drum |25. The connection between planetary gearset III and hydraulic torque converter 3 corresponding to intermediatestructure I2 is effected by means of a second drum |3I, the second drumhowever, being bolted as shown at |32 to the turbine element |33 of theconverter instead of splined as in the first embodiment. The same boltwith a hub portion |2| which comprises the cy- I 6 and that carplanetarygear set II4 has a, lateral extension |21 inwhich the cams of clutchIIS- are formed. Rollers |28 operate between the race and cams to lockthe turbine element |33 to carrier |23 when the turbine element tends torotate ahead of the carrier, and to free the turbine element when thecarrier |23 tends to rotate ahead of the turbine.

The brake operating mechanism for brakes ||8 and |22 may be similar tothat shown in Fig. 3.

driven shaft ||5 when no push start 1 ential for receiving a part Theremainder of the transmission shown in Fig.

is similar to that shown in Fig. 2 with the eX- ception of a sleeve |29which driven shaft H5 and a shaft 35 directly connected to brake H8 andwhich constitutes the reaction member for the torque converter its andthe planetary gear set itil. Said sleeve m9 connects brake |22 directlyto carrier i233 of planetary gear set associated turbine for reversedrive.

It will be observed that the operating linkages of brakes I8 andv 22 areof the servo type, thus requiring less pressure in the operatingcylinders. As the brake bands take hold, they will rock around and lockwith a greater force than that supplied by the oil pressure alone.

It is understood tha-tvarious anti-friction bearing seals, fasteners,etc., may be used as desired or required throughout both embodiments ofthe transmission. It is understood further that the foregoingdescription is merely illustrative of a preferred embodiment of theinvention and that the scope of the invention therefore is not to belimited thereto but it is to be determined by the appended claims.

We claim:

1 .A A variable speed transmission' comprising drive and drivenelements, a power splitting differential, an infinitely variable torquemultiplying device, a stepped-type mechanical torque multiplying deviceand a clutch connected in series functionally, with the power splittingdifferential being connected to the drive element and the clutch'beingconnected to the driven element, and means effecting such seriesconnection, said means disposing said power-splitting differentialremote from the drive element and the clutch adjacent to said driveelement.

2. A variable speed transmission as described in claim 1, saidstepped-type mechanical torque multiplying device being nested withinthe clutch to reduce the length of the transmission.

3. A variable speed transmission comprising input and output structures,a power splitting differential connected to the input structure, an in..termediate structure connected to the differential to receive a part ofthe power, a torque multiplying device connected to the differential toreceive the remainder of the power, means connecting the torquemultiplying device to the intermediate structure to recombine the power,a

element E33 against rotation second torque multiplying device havingreaction,

input, and output members; means connecting the output member to theoutput structure, and selective means for connecting the intermediatestructure either to the input member or to the output structure tosecure either a further multiplication of torque or a direct drive.

4. A variable speed transmission comprising input and output structures,a power splitting differential connected to the input structure, anintermediate structureI connected to the differof the power a torquemultiplying `device connected to the differential to receive theremainder ,of the power, means connecting the torque multiplying deviceto the intermediate structureto recombine the power; a seconddifferential having reaction, input, and output members andI adapted tomultiply torque; means connecting the output member to the outputstructure, friction clutch means for connecting the intermediatestructure to the input member to secure a torque multiplication in the.second differential, and a second clutch for conis inserted between` Htlto hold the latter and its centrically with respect to the' necting theintermediate structure directly to the outlput structure toA bypass thesecond differentia 5. A variable speed transmission comprising input andoutput structures, a power splitting differential connected to the inputstructure, an intermediate structure connected to the differential forreceiving a part of the power, a torque multiplying device connected tothe differential to receive the remainder of the power, means connectingthe torque multiplying device to the intermediate structure to recombinethe power, a second torque multiplying device having reaction, input,and output members; means connecting the output member to the outputstructure, friction clutch means for connecting the intermediatevstructure either to the input member or to the output structure tosecure either a further multiplication of torque or a direct drive, andmeans for interchanging the functions of the reactionand output membersfor reverse drive, the reaction member being driven backwardly by thefirst mentioned torque multiplying device in reverse drive.

6. A variable speed transmission comprising input and output structures,a power splitting differential connected to the input structure, anintermediate structure connected to the differential for receiving apart multiplying device connected to the differential to receive thevremainder of the power, means connecting the torque multiplying deviceto the intermediate structure to recombine the power, a second torquemultiplying device having reaction, input, and output members; meansconnecting the output member tothe output structure, and selective meansfor connecting the intermediate structure either to the input member orto the output structure to secure either a further multiplication oftorque or a direct drive, said input structure including a'drum whichencloses the rst and second torque multiplying devices and the selectivemeans.

7. A variable speed transmission comprising an input shaft, an outputshaft aligned with and piloted in the end of said input shaft, adifierential, a hydrodynamic torque converter adjacent the differential,a friction clutch adjacent the hydrodynamic torque converter, and asecond differential adjacent the clutch, said differentials,torque'converter and clutch being arranged conoutput shaft, and meansconnecting said first differential to the input shaft, said firstdifferential being remote from the input shaft, said second differentialbeing positioned adjacent said input shaft, and the hydrodynamic torqueconverter and clutch being disposed between the differentials; meansoperatively connecting the first differential to the torque converter,clutch and second differential; and a drum connecting the input shaftptothe first differential, said drum completely enclosing the torqueconverter, clutch and first differential.

8. A variable speed transmission comprising an input shaft, an outputshaft aligned with and piloted in said input shaft, a planetary gear setcoaxial with the driven' shaft and spaced from 'the input shaft, a drumconnecting the input shaft to the planetary gear set, a second drumwithin the first drum and connected at one end to the planetary lgearset, a hydrodynamic torque converter within *the second drum andconnected thereto and to the planetary gear set,y a second planetarygear set positioned between .the torque converter and the input shaft,clutch means for of the power, a torque connecting thesecond planetarygear set to the second drum, and means for connecting the secondplanetary gear set to the output shaft.

9. A Variable speed transmission as described in claim 8, said first andsecond planetary gear sets comprising ring, sun and planet gears and acarrier for the planet gears; the rst-.mentioned drum being connected tothe ring gear of the rst panetary gear set, the second drum beingconnected to the carrier of the first planetary gear set, the clutchbeing connected to the carrier of the second planetary gear set, theoutput shaft being connected to the ring gear on the second planetarygear set, the sun gear of the second planetary gear set constituting thereaction element-.for the transmission, and the sun gear of the rstplanetary gear set constitut ing the connection between said firstplanetary gear set and the hydrodynamic device.

10. A variable speed transmission as described in claim 8, and clutchmeans for connecting the second drum directly to the driven shaft torender the second planetary gear set ineffective.

11. A transmission as described in claim 8, and a clutch for directlyconnecting the driven shaft to the second drum to render the secondplanetary gear set ineffective, said last-mentioned clutch beingtelescoped over the second planetary gear set.

12. A variable speed transmission comprising an input shaft, an outputshaft coaxial with and piloted in the input shaft, a planetary gear setcomprising ring, planet and sun gears and a carrier for the planetgears; a hydraulic torque converter comprising pump, turbine and statorelements; a second planetary gear set comprising ring, planet and sungears and a carrier for the planet gears; a drum connecting the inputshaft to the ring gearof the first planetary set; a drum connecting thecarrier oi the first planetary gear set to the turbine element of thehydraulic torque converter, means connecting the pump element to the sungear of the rst planetary gear set, a clutch Within the second drum andadapted to connect said drum to the carrier of the second planetary gearset which is also positioned Within thesecond drum, means for connectingthe ring gear of the second planetary gear set to the output shaft, abrake outside of the drums and adapted to. be connected to the statorand to the sun gear of the second planetary gear set to provide areaction therefor, and a second brake, also outside of the drums, anddirectly connected to the carrier of the `rst mentioned planetary gearset,

13. A power transmitting mechanism comprising input and outputstructures, a differential gear set comprising ring, sun and dual planetgears and a carrier for the planet gears, means connecting the ring'gear to the output structure, a torque multiplying device, meansconnecting the device to the input structure, a brake for the i sun gearto provide a reaction for torque multireaction elements, one of saidelements when held against rotationcausing the second element to rotateforwardly and the second element when braked causing the rst element to`rotate reversely, means connecting the device to the input structure,means connecting the iii-st said reaction element to the sun gear, atwo-way clutch for connecting the second element to the outputstructure, a one-way clutch for connecting the second element to'thecarrier when the two-Way clutch is disengaged, ibrake means for the sungear to provide a reaction for torque multiplica tion, and brake meansfor the carrier to cause the rst element to act as a reaction element,the reaction on the carrier brake means being in a direction to .renderthe one-way clutch means effective.

15. A power transmitting mechanism comprising input and outputstructures, a differential gear set comprising ring, sun and dual planetgears and a carrier for the planet gears, means connecting the ring gearto the output structure, a hydrodynamic torque converter having pump,turbine and stator elements, means connecting the pump element to theinput structure, a brake for the `sun gear to provide a reaction fortorque multiplication in the gear set, a two-way clutch for connectingthe converter to the output structure when no torque multiplication isdesired in the gear set, a one-Way coupling effective to connect thecarrier to the turbine element when'the turbine element is the driver,and .a brake for holding the carrier against rotation,v said brake beingeiective through the one-way coupling to hold the turbine elementagainst rotation, whereby the functions of the turbine and. statorelements mayl be interchanged to produce a reverse drive in the outputstructure.

HAROLD E. CARNAGUA. DONALD W. KEIIIIBEL.V

